Silicon-controlled rectifier electrostatic discharge protection device and method for forming the same

Patent metadata

Field	Value
Publication number	US-9520488-B2
Application number	US-201414332534-A
Country	US
Kind code	B2
Filing date	Jul 16, 2014
Priority date	Dec 30, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

Various embodiments provide SCR ESD protection devices and methods for forming the same. An exemplary device includes a semiconductor substrate having a P-type well region, an N-type well region adjacent to the P-type well region, a first P-type doped region and a first N-type doped region in the P-type well region, and a second N-type doped region and a second P-type doped region in the N-type well region. A first center-doped region and a second center-doped region doped with impurity ions of a same type are located between the first N-type doped region and the second P-type doped region and extend across the P-type well region and the N-type well region. The first center-doped region is located within the second center-doped region, has a doping concentration higher than a doping concentration in the second center-doped region, and has a depth smaller than a depth of the second center-doped region.

First claim

What is claimed is:

1. A silicon-controlled rectifier (SCR) electrostatic discharge protection (ESD) device, comprising:
a semiconductor substrate having a P-type well region and an N-type well region adjacent to the P-type well region;
a first P-type doped region in the P-type well region;
a first N-type doped region in the P-type well region between the first P-type doped region and the N-type well region;
a second N-type doped region in the N-type well region;
a second P-type doped region in the N-type well region between the second N-type doped region and the P-type well region; and
a first center-doped region and a second center-doped region, wherein the first center-doped region and the second center-doped region are located between the first N-type doped region and the second P-type doped region and extend across the P-type well region and the N-type well region, the first center-doped region is located within and enclosed by the second center-doped region, the second center-doped region has a depth greater than a depth of the first center-doped region, and the first center-doped region and the second center-doped region are doped with impurity ions of a same type, a concentration of the impurity ions in the first center-doped region being higher than a concentration of the impurity ions in the second center-doped region.

2. The device according to claim 1 , wherein:
the impurity ions doped in the first center-doped region and the second center-doped region are N-type,
the depth of the second center-doped region is smaller than a depth of the N-type well region, and
the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the N-type well region.

3. The device according to claim 2 , wherein
the concentration of the impurity ions in the N-type well region is less than about 1E18 atom/cm 3 ,
the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm 3 to about 1E19 atom/cm 3 , and

the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm 3 .

4. The device according to claim 1 , wherein:
the impurity ions doped in the first center-doped region and the second center-doped region are P-type,
the depth of the second center-doped region is smaller than a depth of the P-type well region, and
the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the P-type well region.

5. The device according to claim 4 , wherein
the concentration of the impurity ions in the P-type well region is less than about 1E18 atom/cm 3 ,
the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm 3 to about 1E19 atom/cm 3 , and
the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm 3 .

6. The device according to claim 1 , further comprising a shallow trench isolation (STI) structure between adjacent doped regions.

7. The device according to claim 1 , wherein the concentration of the impurity ions in the second center-doped region is gradually increased from a lower surface of the second center-doped region to an upper surface of the second center-doped region.

8. The device according to claim 1 , wherein:
the first N-type doped region contains a plurality of discrete third P-type doped regions to divide the first N-type doped region into a plurality of first N-type sub-doped regions, and
one discrete third P-type doped region is between and in contact with adjacent first N-type sub-doped regions.

9. The device according to claim 1 , wherein:
the second P-type doped region contains a plurality of discrete third N-type doped regions to divide the second P-type doped region into a plurality of second P-type sub-doped regions, and
one discrete third N-type doped region is between and in contact with adjacent second P-type sub-doped regions.

10. The device according to claim 1 , wherein the first center-doped region and the second center-doped region are co-centered.

11. The device according to claim 1 , wherein the first N-type doped region, the P-type well region, and the second center-doped region form a parasitic NPN transistor.

12. A method for forming an SCR ESD device, comprising:
providing a semiconductor substrate;
forming, in the semiconductor substrate, a P-type well region and an N-type well region adjacent to the P-type well region;
forming a second center-doped region that extends across the P-type well region and the N-type well region;
forming a first center-doped region in and enclosed by the second center-doped region, a depth of the second center-doped region being greater than a depth of the first center-doped region, wherein the first center-doped region and the second center-doped region are doped with impurity ions of a same type, a concentration of the impurity ions in the first center-doped region being higher than a concentration of the impurity ions in the second center-doped region;
forming a first P-type doped region in the P-type well region at a first side of the second center-doped region;
forming a first N-type doped region in the P-type well region at the first side of the second center-doped region, the first N-type doped region being located between the first P-type doped region and the second center-doped region;
forming a second N-type doped region in the N-type well region at a second side of the second center-doped region; and
forming a second P-type doped region in the N-type well region at the second side of the second center-doped region, the second P-type doped region being located between the second N-type doped region and the second center-doped region.

13. The method according to claim 12 , wherein:
the impurity ions doped in the first center-doped region and the second center-doped region are N-type,
the depth of the second center-doped region is smaller than a depth of the N-type well region, and
the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the N-type well region.

14. The method according to claim 13 , wherein
the concentration of the impurity ions in the N-type well region is less than about 1E18 atom/cm 3 ,
the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm 3 to about 1E19 atom/cm 3 , and
the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm 3 .

15. The method according to claim 12 , wherein:
the impurity ions doped in the first center-doped region and the second center-doped region are P-type,
the depth of the second center-doped region is smaller than a depth of the P-type well region, and
the concentration of the impurity ions in the second center-doped region is higher than a concentration of impurity ions in the P-type well region.

16. The method according to claim 15 , wherein
the concentration of the impurity ions in the P-type well region is less than about 1E18 atom/cm 3 ,
the concentration of the impurity ions in the second center-doped region ranges from about 1E18 atom/cm 3 to about 1E19 atom/cm 3 , and
the concentration of the impurity ions in the first center-doped region is higher than about 1E19 atom/cm 3 .

17. The method according to claim 12 , further comprising:
forming an STI structure between adjacent doped regions.

18. The method according to cla

Assignees

• Semiconductor Mfg Int Shanghai Corp

Inventors

• Dai Meng

Classifications

• H10D62/115

  Dielectric isolations, e.g. air gaps · CPC title

• H10D62/108

  having localised breakdown regions, e.g. built-in avalanching regions  (in self-protected thyristors H10D18/211) · CPC title

• H10D89/713

  including a PNP transistor and a NPN transistor, wherein each of said transistors has its base region coupled to the collector region of the other transistor, e.g. silicon controlled rectifier [SCR] devices · CPC title

• H10D8/80

  PNPN diodes, e.g. Shockley diodes or break-over diodes · CPC title

• H10D8/041 Primary

  of multilayer diodes · CPC title